/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.reactive.socket.adapter;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import javax.websocket.CloseReason;
import javax.websocket.CloseReason.CloseCodes;
import javax.websocket.SendHandler;
import javax.websocket.SendResult;
import javax.websocket.Session;

import reactor.core.publisher.Mono;
import reactor.core.publisher.MonoProcessor;

import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.lang.Nullable;
import org.springframework.web.reactive.socket.CloseStatus;
import org.springframework.web.reactive.socket.HandshakeInfo;
import org.springframework.web.reactive.socket.WebSocketMessage;
import org.springframework.web.reactive.socket.WebSocketSession;

/**
 * Spring {@link WebSocketSession} adapter for a standard Java (JSR 356)
 * {@link javax.websocket.Session}.
 *
 * @author Violeta Georgieva
 * @author Rossen Stoyanchev
 * @since 5.0
 */
public class StandardWebSocketSession extends AbstractListenerWebSocketSession<Session> {

    public StandardWebSocketSession(Session session, HandshakeInfo info, DataBufferFactory factory) {
        this(session, info, factory, null);
    }

    public StandardWebSocketSession(Session session, HandshakeInfo info, DataBufferFactory factory,
                                    @Nullable MonoProcessor<Void> completionMono) {

        super(session, session.getId(), info, factory, completionMono);
    }


    @Override
    protected boolean canSuspendReceiving() {
        return false;
    }

    @Override
    protected void suspendReceiving() {
        // no-op
    }

    @Override
    protected void resumeReceiving() {
        // no-op
    }

    @Override
    protected boolean sendMessage(WebSocketMessage message) throws IOException {
        ByteBuffer buffer = message.getPayload().asByteBuffer();
        if (WebSocketMessage.Type.TEXT.equals(message.getType())) {
            getSendProcessor().setReadyToSend(false);
            String text = new String(buffer.array(), StandardCharsets.UTF_8);
            getDelegate().getAsyncRemote().sendText(text, new SendProcessorCallback());
        } else if (WebSocketMessage.Type.BINARY.equals(message.getType())) {
            getSendProcessor().setReadyToSend(false);
            getDelegate().getAsyncRemote().sendBinary(buffer, new SendProcessorCallback());
        } else if (WebSocketMessage.Type.PING.equals(message.getType())) {
            getDelegate().getAsyncRemote().sendPing(buffer);
        } else if (WebSocketMessage.Type.PONG.equals(message.getType())) {
            getDelegate().getAsyncRemote().sendPong(buffer);
        } else {
            throw new IllegalArgumentException("Unexpected message type: " + message.getType());
        }
        return true;
    }

    @Override
    public Mono<Void> close(CloseStatus status) {
        try {
            CloseReason.CloseCode code = CloseCodes.getCloseCode(status.getCode());
            getDelegate().close(new CloseReason(code, status.getReason()));
        } catch (IOException e) {
            return Mono.error(e);
        }
        return Mono.empty();
    }


    private final class SendProcessorCallback implements SendHandler {

        @Override
        public void onResult(SendResult result) {
            if (result.isOK()) {
                getSendProcessor().setReadyToSend(true);
                getSendProcessor().onWritePossible();
            } else {
                getSendProcessor().cancel();
                getSendProcessor().onError(result.getException());
            }
        }

    }

}
